LXR linux/net/core/netclassid

   1/*
   2 * net/core/netclassid_cgroup.c Classid Cgroupfs Handling
   3 *
   4 *              This program is free software; you can redistribute it and/or
   5 *              modify it under the terms of the GNU General Public License
   6 *              as published by the Free Software Foundation; either version
   7 *              2 of the License, or (at your option) any later version.
   8 *
   9 * Authors:     Thomas Graf <tgraf@suug.ch>
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/slab.h>
  14#include <linux/cgroup.h>
  15#include <linux/fdtable.h>
  16#include <net/cls_cgroup.h>
  17#include <net/sock.h>
  18
  19static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
  20{
  21        return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
  22}
  23
  24struct cgroup_cls_state *task_cls_state(struct task_struct *p)
  25{
  26        return css_cls_state(task_css_check(p, net_cls_cgrp_id,
  27                                            rcu_read_lock_bh_held()));
  28}
  29EXPORT_SYMBOL_GPL(task_cls_state);
  30
  31static struct cgroup_subsys_state *
  32cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
  33{
  34        struct cgroup_cls_state *cs;
  35
  36        cs = kzalloc(sizeof(*cs), GFP_KERNEL);
  37        if (!cs)
  38                return ERR_PTR(-ENOMEM);
  39
  40        return &cs->css;
  41}
  42
  43static int cgrp_css_online(struct cgroup_subsys_state *css)
  44{
  45        struct cgroup_cls_state *cs = css_cls_state(css);
  46        struct cgroup_cls_state *parent = css_cls_state(css->parent);
  47
  48        if (parent)
  49                cs->classid = parent->classid;
  50
  51        return 0;
  52}
  53
  54static void cgrp_css_free(struct cgroup_subsys_state *css)
  55{
  56        kfree(css_cls_state(css));
  57}
  58
  59static int update_classid_sock(const void *v, struct file *file, unsigned n)
  60{
  61        int err;
  62        struct socket *sock = sock_from_file(file, &err);
  63
  64        if (sock)
  65                sock->sk->sk_classid = (u32)(unsigned long)v;
  66
  67        return 0;
  68}
  69
  70static void update_classid(struct cgroup_subsys_state *css, void *v)
  71{
  72        struct css_task_iter it;
  73        struct task_struct *p;
  74
  75        css_task_iter_start(css, &it);
  76        while ((p = css_task_iter_next(&it))) {
  77                task_lock(p);
  78                iterate_fd(p->files, 0, update_classid_sock, v);
  79                task_unlock(p);
  80        }
  81        css_task_iter_end(&it);
  82}
  83
  84static void cgrp_attach(struct cgroup_taskset *tset)
  85{
  86        struct cgroup_subsys_state *css;
  87
  88        cgroup_taskset_first(tset, &css);
  89        update_classid(css,
  90                       (void *)(unsigned long)css_cls_state(css)->classid);
  91}
  92
  93static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
  94{
  95        return css_cls_state(css)->classid;
  96}
  97
  98static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
  99                         u64 value)
 100{
 101        struct cgroup_cls_state *cs = css_cls_state(css);
 102
 103        cs->classid = (u32)value;
 104
 105        update_classid(css, (void *)(unsigned long)cs->classid);
 106        return 0;
 107}
 108
 109static struct cftype ss_files[] = {
 110        {
 111                .name           = "classid",
 112                .read_u64       = read_classid,
 113                .write_u64      = write_classid,
 114        },
 115        { }     /* terminate */
 116};
 117
 118struct cgroup_subsys net_cls_cgrp_subsys = {
 119        .css_alloc              = cgrp_css_alloc,
 120        .css_online             = cgrp_css_online,
 121        .css_free               = cgrp_css_free,
 122        .attach                 = cgrp_attach,
 123        .legacy_cftypes         = ss_files,
 124};
 125